The invention refers to an electromotor comprising a rotor rotatably running on bearings on a rotor shaft and a stator surrounding the rotor, the stator having a short-circuit body and a winding which can be impinged by current and the electromotor having at least one medium line.
Electromotors of this type are employed for example for driving rotating dental or medical instruments. For this purpose the rotating instruments, for example drills or the like, are put on the electromotor via a standard coupling. The dental instrument has to be supplied during employment with different supply media via one or more medium lines. For example, in the dental field of employment spray air, spray water, cooling air, current, light and so on are required which have to be supplied through the electromotor to the driven dental instruments in the tool head. The medium lines have, of course, a certain diameter and have to be integrated in the area of the motor, where, as it is known, corresponding dental instruments as hand-held instruments are not supposed to exceed certain exterior dimensions, in order to not impair operating and handling. At the same time the electromotor, however, has to provide a sufficient turning moment and number of rotations.
In the state of the art several solutions have been known showing a passage of a medium line through the short-circuit body of a motor. All solutions of the state of the art which have become known comprise here solutions which deal exclusively with cooling of the motor or the short-circuit body.